The resistor assembly disclosed hereinbelow is primarily intended for diesel electric locomotives and similar vehicles. The heat generated in braking and the vibration of the moving vehicle are detrimental to the service life of resistor units in that service. Resistor units presently intended for that service are described in U.S. Pat. No. 2,680,178 issued to C. W. Kuhn et al. on June 1, 1954; U.S. Pat. No. 2,874,257, also to Kuhn et al. on Feb. 17, 1959 and U.S. Pat. No. 4,316,172 issued to William R. Luy on Feb. 16, 1982. The structure of those articles may be described as relatively narrow flat strips of resistor material reflexed or fan-folded in a frame containing two or more units arranged side by side. Such a structure facilitates the provision of taps for fan or otherwise at the junction of such units.
The electrical resistance of flat-strip resistor material is a function both of the dimensions of the strip, its chemical composition ad its processing. It would be desirable from the manufacturing standpoint to make resistor assemblies or grids from a small number of units of wide strip and, in fact, such a structure is disclosed in Harness U.S. Pat. Nos. 4,651,125 and 4,654,627 of Mar. 17 and Mar. 31, 1987, respectively. The Harkness grid members occupy the full width of the frame but they have no taps.